1. Technical Field
The present invention generally relates to fuel cell technology field and, more particularly to a fuel cell system and a power management method thereof.
2. Description of the Related Art
A fuel cell makes use of the combination of hydrogen and oxygen to generate a chemical reaction and has been become as a novel energy resource for supplying electrical power. After the fuel cell is activated to achieve normal electrochemical reaction efficiency, a fuel cell power generation part of the fuel cell is required to output an electrical power with constant power so that the fuel cell may attain relatively high power generation efficiency. In addition, an output voltage of the fuel cell power generation part is inversely proportional to the output current thereof. That is, when there is no output current, the output voltage of the fuel cell power generation part is maximum; as the output current increases, the output voltage would decrease correspondingly. Moreover, in the case of the output currents are the same, the larger the output power of the fuel cell power generation part, the higher the output voltage.
A fuel cell system in the prior art includes a fuel cell power generation part and a load supply circuit. The load supply circuit is for transforming electrical power provided from the fuel cell power generation part into a specific output voltage and supplying the output voltage to an external load and/or an internal system device for use, as proposed in, for example Taiwanese Patent No. 1274454, Taiwanese Patent Publication No. 200743240 and U.S. patent Publication No. 2008/0036432, the disclosures of which are incorporated herein by references.
However, when the output power of the fuel cell power generation part is increased, voltage tolerance specifications of main circuit components (e.g., buck&boost integrated circuits) in the load supply circuit are needed to increase correspondingly, the use of many components with high voltage tolerance specification may cause increased cost for the entire fuel cell system.